CakePHP association one Model to exclusively one out of three others? - database

Question

i got a problem with designing my Database and the CakePHP code around it.
I have 4 Models,
ServerName
VirtualMachine
ServerHousing
ManagedServer
In ServerName, i want to save all ServerNames which then can be used in either one of the three other models. How can i achieve that i am only able to link one ServerName to either one of the other models?
Thank you guys in advance.
EDIT:
I now did it a little bit different. First of all it need to be done in the Model itself.
I used the validate option in cakePHP's models.
The code is like this:
public $validate = array(
'server_name_id' => array(
'rule' => 'serverNameTaken',
'message' => 'This Servername has already been taken.'
)
);
public function serverNameTaken()
{
$this->ManagedServer = ClassRegistry::init("ManagedServer");
// Assuming the server_name_id was passed from the form...
$server_name_id = $this->data['VirtualMachine']['server_name_id'];
// Check if this servername_id is already saved in virtual_machines
if ($this->ManagedServer->find('count', array(
'conditions' => array(
'ManagedServer.server_name_id' => $server_name_id
)
)) > 0
) {
// Found the server_name in the VirtualMachine model!
return false; // Prohibit saving the data
}
if ($this->find('count', array(
'conditions' => array(
'VirtualMachine.server_name_id' => $server_name_id
)
)) > 0
) {
// Found the server_name in the VirtualMachine model!
return false; // Prohibit saving the data
}
// Do this for the other models too. If a return false is not hit by now,
// everything should be fine and you can...
return true;
}
Same code I used in the other models, only the code had to be altered.
Thanks again for you answer!!!

Answer 1

You can't do this on the Model layer. Models are either associated or they are not. What you are probably looking for is some logic in your Controller that checks if a row for ServerName X has already been saved in any of the other models, prior to saving it from another model.
The beforeSave function is useful for this. For example, in your Controller, put this:
public $uses = array('VirtualMachine', 'ServerHousing', 'ManagedServer');
public function beforeSave() {
// Assuming the servername_id was passed from the form...
$servername_id = $this->request->data['servername_id'];
// Check if this servername_id is already saved in virtual_machines
if($this->VirtualMachine->find('count', array(
'conditions' => array(
'VirtualMachine.servername_id' => $servername_id
)
)) > 0) {
// Found the servername in the VirtualMachine model!
return false; // Prohibit saving the data
}
// Do this for the other models too. If a return false is not hit by now,
// everything should be fine and you can...
return true;
}
Hope this will get you going in the right direction.